The general purpose of this study is to examine under what conditions crowding affects the behavior of children. The first stage of the research shall consist of controlled experimental studies on the effects of various densities, scarcity of resources, and situational variables on the social and affective behavior of children. In comparing the effects of differing densities, space and number of children shall be varied. The effects on behavior of relative abundance or scarcity of important resources of the physical environment shall be studied by varying the availability of valued toys, food, and space. The effect of situational variables on the experience of crowding shall be assessed by varying the structure of the activities and architecture of the setting. Sex differences in response to crowding shall be assessed as well as the effects of density on children of various levels of impulsivity. Behavioral observations shall be used for the dependent social variables and rating scales shall be used for the affective measures. Children will undergo free play in various sized groups in various sized rooms and shall be rated from behind a one-way mirror.